电场对酸盐的分解的影响
Zhaoran Zhu1, James P Ewen1, Efstratios M Kritikos2,1
1Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, U.K.
概括
电场加速了金属表面上的三丁酸盐 (TNBP) 的分解,影响了电动汽车滑油等应用中的保护膜形成. 模拟显示了铁和氧化铁表面的场所驱动的不对称生长和改变的分解路径.
科学领域:
- 三角学和表面化学.
- 计算材料科学科学 计算材料科学
- 电化学 电化学 电化学
背景情况:
- 酸在金属表面上形成保护膜,对于tribological应用至关重要.
- 电场对分子分解和薄膜形成的影响尚不清楚,实验数据相互矛盾.
- 了解这些影响对于电动汽车和风力轮机中的滑油至关重要.
研究的目的:
- 通过模拟,研究静电场对在铁表面之间纳米封闭的三丁酸盐 (TNBP) 的分解的影响.
- 在应用电场下比较不同的电荷建模方法 (QTPIE与QEq).
- 阐明TNBP分解和薄膜生长中电场诱导加速和不对称的背后机制.
主要方法:
- 没有平衡的分子动力学 (NEMD) 模拟.
- 反应力场 (ReaxFF) 用于模拟化学结合和解离.
- 使用极化电流平衡 (QTPIE) 和电荷平衡 (QEq) 方法进行电荷转移.
- 阿雷尼乌斯方程分析和单分子推推弹性带 (NEB) 计算.
主要成果:
- 由于表面催化,TNBP在纳米封闭的铁表面上的分解速度比散装更快.
- 应用的电场始终在铁和氧化铁表面加速TNBP的分解.
- 电场通过将酸盐离子和酸盐离子指向负电相反的表面来诱导不对称膜的生长.
- 在铁表面上,加速分解与碰撞频率的增加有关 (预指数因子);在氧化铁上,这是由于激活能量的减少.
- NEB的计算证实,随着电场强度的增加,C-O键断能量屏障的线性减少.
结论:
- 与QEq.q.相比,QTPIE方法在电场下的分子行为提供了更现实的模拟.
- 电场显著改变TNBP分解动力学,并导致不对称的 tribofilm 形成.
- 模拟结果与在静电场下增强和不对称的 tribofilm 增长的实验观测一致,提供了机械洞察力.
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